Hi all. Just finished my 455". .030 over, Eagle rods, Icon 9-1 pistons, cloyes timing set, EB alum heads, Howard 4/7 swap roller cam(wiring is correct) ((int. .225-Exh. .229 - .560 int, .555 exh. - 4 degrees adv. from factory)), 1.6/1 roller rockers, Quickfuel 880 CFM carb, D.U.I. vacuum Ad. Dist. calibrated to 24 Degrees @3000 rpm. I'm having a real problem timing this thing. I've set it up @0 on the timing mark w/rotor pointing @#1 cylinder. It will fire up but blows black smoke and acts as if it's not running on all cylinders. I even jumped the dist. a tooth (because the vacuum can on the dist. doesn't have much room to rotate) and it actually ran better. Is this where i should factor in the INITIAL Advance timing by setting the timing mark to 8?10?12? BTDC and point the dist. to #1? Any help will be greatly appreciated. many thanks. Bill, wfg4u@aol.com.

 

Using a timing light I'd set initial to 12 assuming that it has 24 deg's of mechanical advance. What is the vacuum canister rated? It should be a 10 deg canister. You need to make sure your distributor is installed so there is room to adjust it without hitting the engine or firewall.

I think it will be lazy the way its set up because your cam will probably like more initial and less mechanical.

 

Hi Oldcutlass. I can move the distributor about 2 inches @the most. To set the initial timing should I set the timing mark on the crank to 0? 4? 6? 8 degrees btdc? And the rotor pointing @ the #1 cylinder in the distributor? Sorry, guess i just don't get it. I can't get it running well enough or long enough to use a timing light. Where do i start? Many Thanks again, Bill. wfg4u@aol.com

 

You can set the timing with the light hooked up while the engine is cranking.

Just make sure that the rotor is pointed to #1, turn up the idle speed screw on the carb a bit, and crank the engine. If its backfiring through the carb and won't run it may be 180 degrees out. Which means you need to note the current position of the rotor, pull the distributor and turn the rotor 180 degrees and reinstall the distributor. Then try again.

 

Hi All. Has anyone had any experience with a 4/7 swap camshaft? I can't seem to get this engine timed much less fire up. At normal timing it wants to start but won't. When I change diet. timing (skip teeth either way) it either won't start at all or it will run but as if it's running on about 4 cylinders. This is a Howard full roller setup in a 455". All wiring is correct. Any Help? Thanks. wfg4u@aol.com

 

I moved your question back to your original problem post. This way there is some history of whats going on. The 4/7 cam works just like any other cam with the exception that the 4 and 7 wires are swapped in the firing order.

Did you do what I suggested in my last post?

 

Hi Oldcutlass. I set the crank marker @ 0 degrees on the compression stroke. I then set the Dist pointing @ #1 cylinder on the cap. It wants to start but won't. I then advanced the Dist (in small increments, even jumped teeth after i ran out of dist travel room) several degrees until it wanted to run on about 4 cylinders. I also tried retarding it to no avail. Could this possibly be a cam timing problem from initial assembly? many thanks, Bill. wfg4u@aol.com

 

Did you check and make sure you had full battery voltage on your hei? Is your firing order 18736542 wired CCW on the cap. Is your choke fully open? Do you have 2 solid streams of fuel spraying into the carb with the engine off operating the throttle by hand? Are your plugs gapped at .045? Are all your wires on tight at the cap and plugs.

 

You may wish to double verify that 4-7 got swapped cam-wise.